One way to increase the power and fuel efficiency of a gas turbine engine is to increase the temperature of the combustion gases to the maximum level that the turbine and nozzle structures will withstand. The maximum turbine rotor inlet temperature allowed by current state-of-the-art uncooled metal turbine rotors is approximately 2050.degree. F. Increasing the turbine rotor inlet temperature beyond 2050.degree. F. requires the use of advanced super alloy blade materials which are generally not compatible with rotor disk mechanical property requirements.
A solution to this incompatibility problem is to adopt a dual-property approach to the fabrication of the turbine rotor. In large gas turbines, where size and complexity constraints are not acute, this is accomplished by using discrete blades of a high rupture strength material mechanically attached to a high burst strength disk. However, the physical size, cost, and complexity associated with this dual-property rotor concept have precluded its use in small, lightweight gas turbine engines.